/Engine/Source/Runtime/Engine/Classes/GameFramework/Actor.h
including the ones added via the BP editor (whichAActor.GetComponentsfails to do for CDOs).
template<typename TComponentClass, typename> static void GetActorClassDefaultComponents ( const [TSubclassOf](API\Runtime\CoreUObject\Templates\TSubclassOf)< [AActor](API\Runtime\Engine\GameFramework\AActor) > & InActorClass, [TArray](API\Runtime\Core\Containers\TArray)< const TComponentClass * > & OutComponents )